(CNN) -- Gas prices have jumped nearly 20 cents over the past two weeks, approaching the all-time high, according to a survey published Sunday.
The average price of a gallon of self-serve regular is $3.76, the Lundberg Survey found. The previous survey three weeks ago found an average of $3.57.
That means prices are now just 35 cents -- "within firing range" -- of the all-time high of $4.11 set in July 2008, said publisher Trilby Lundberg.
"This doesn't mean that we will get there," she said. "Crude oil will decide."
Crude prices have been impacted by the unrest in the Middle East, she said, but also by two other major underlying factors: increased demand in developing nations and the weak dollar.
"Unless crude oil relents and slips, we can expect a further rise at the pump because pump prices do not reflect all of the crude oil price hikes that have occurred," Lundberg said.
CNNMoney.com: All eyes on oil and earnings
The latest Lundberg survey, which tabulates prices at thousands of gas stations nationwide, took place on Friday. Of the cities surveyed that day, the lowest average price was in Tucson, Arizona, at $3.41. The highest average price was in the San Francisco Bay area at $4.13.
Here are the average prices in some other cities:
-- Chicago - $4.11
-- Seattle - $3.85
-- Boston - $3.71
-- Houston - $3.67
-- Atlanta - $3.61
-- Memphis, Tennessee - $3.56
-- Denver - $3.49
Gas prices in 'firing range' of all-time high
